Sök:

Sökresultat:

20 Uppsatser om Inbreeding - Sida 1 av 2

Hur påverkar inavel fruktsamheten hos häst?

Inbreeding has become a problem in some horse breeds. Studies show that it may lead to Inbreeding depression which affects e.g. reproduction traits. In the wild there are mechanisms that make horses avoid mating with close relatives. When selection is done by humans this mechanism is removed and intensive breeding for a few traits, for example good racing results, can become a problem.

Genetisk studie av inavel och fertilitet hos hund :

Inbreeding, the mating of related individuals, has been the one dominating breeding strategy for dog breeders during the last 200 years. However, its negative effects on fer-tility and other fitness traits, a phenomenon called Inbreeding depression, have been ignored in the quest of perfect unity in conformation or performance. The purpose of this study was to test the hypotheses that litter size is reduced as a consequence of in-breeding, affected by both the Inbreeding coefficient of the dam and the litter and that a rapid increase in the Inbreeding coefficient affects litter size more than a slower rate. Data were collected from the Swedish Kennel Club registry of origin. Breeds included in the study were the Bernese Mountain Dog, the Cocker Spaniel, the Golden Retriever, the Rottweiler and the West Highland White Terrier.

Populationsstruktur och genetisk analys av exteriöra egenskaper hos svensk ardenner :

The purposes of this study were to estimate genetic and phenotypic parameters for conformation traits in Swedish Ardenner, a heavy draught horse, and to investigate the Inbreeding status of the population. Additionally, a breeding scheme proposal was created, based on the results achieved in the study. The data studied were obtained from the Swedish Horse Board and from the Swedish Ardenner Association. The data included 1632 three-year-old horses, mainly mares, and 356 stallions, judged between 1986 and 2005 at conformation shows. The traits studied were type, head-neck-body, legs, walk and trot at hand, total score and height at withers.

Latitudinal patterns in body size of Roesel?s bush cricketMetrioptera roeselii within and outside the continuous area of its distribution

Over time, species colonize new areas naturally or through humans. The colonizers areoften few and founded populations represent only a fraction of the genetic diversityexisting in the original population. If the established population becomes isolated afterthe colonization event genetic diversity will remain low and if the population, in addition,remains small in size for an extended period this will lead to increased Inbreeding andpossibly Inbreeding depression. Metrioptera roeselii is a common species with awidespread distribution in continental Europe. During the last century, it has expanded tothe Scandinavian Peninsula which is separated from continental Europe by the Baltic Sea.My aim was to test the hypothesis that individuals in isolated populations in Scandinaviaincluding Denmark and the Baltic Sea islands are smaller than individuals in thecontinuous part of its distribution due to low genetic diversity and lacking incoming geneflow.

Fortplantning och fortplantningsproblem hos tikar av svensk och finsk lapphund : en jämförande studie

The Swedish Lapphund is one of our eleven Swedish domestic breeds of dogs and one of Sweden?s oldest dogbreeds. The Finnish Lapphund?s origin and physical conformation is similar to that of the Swedish Lapphund. One aim of this study was to examine whether the average litter size differs between these two closely related breeds, and if so, try to find causes for this.

Analys av dräktighets- och fölningsresultat inom svensk varmblodig ridhäst och svensk varmblodig travhäst åren 2000-2006

The purpose of this thesis was to analyze conception and foaling results of Swedish warmblood and Standardbred trotters using breeding statistics during the years 2000-2006. Key issues in this thesis were: Have the conception and foaling results of stallions changed during the period 2000-2006? What is the effect of the use of various breeding methods? Is testicle size correlated with conception and foaling results? How important are age, breed and level of Inbreeding of the stallion for conception and foaling results? Breeding statistics were available for 537 Swedish Warmblood stallions and 305 Standardbred trotter stallions. To be included in the analyses, a stallion must have mated at least ten mares in total over the period 2000-2006. This criterion was met by 313 Swedish Warmblood stallions and 272 Standardbred trotter stallions.

Genomisk selektion och uppbyggnaden av avelsprogram hos mjölkkor

During the last decade a new technique in animal breeding has developed called genomic selection. It is based on estimations of the effect from genetic markers on traits that are calculated in a reference population. By genotyping individuals, genomic breeding values can then be estimated without phenotypic observations. The aim of this essay is to investigate the response of genomic selection on breeding schemes for dairy cattle. The accuracy of the genomic breeding values is affected by the proportion of observations included in the validation set and how often the equation for estimating breeding values is reevaluated.

Estimation of heterosis and performance of crossbred Swedish dairy cows

The heterosis effect and breed group effect of crossbreds between Swedish Holstein (SH) and Swedish Red (SRB) was estimated in this study. Observations on cows born between 1990 and 2012 were used to estimate the heterosis effect and breed group effect for several traits included in the Nordic breeding goals: production, fertility, udder health, calving performance, survival and other diseases. Breeding within the Holstein dairy breed has earlier been focused on increased milk production and conformation. This, combined with an intensive use of individual animals, has resulted in a radical increase of milk yield in the Holstein dairy cow population all over the world. However, this breeding strategy has resulted in increased Inbreeding and several functional traits have impaired.

Crossbreeding in dairy cattle

The aim of this literature review is to give an overview of the differences between pure- and crossbreeding systems. Crossbreeding is a mating system with individuals of different lines or breeds. It is one of several breeding strategies in dairy production used to increase the economic profit. The use of crossbreeding increases due to changes in the dairy market and an increase of Inbreeding among purebred Holstein. The main benefit of crossbreeding is heterosis, which is the improvement in genetic level in a hybrid offspring above the average of the parent breeds.

Den svenska lapphunden - en ras i behov av förändring?

Many pedigree dogs are suffering from inherited diseases or personality disorders caused by selective breeding. The Swedish lapphund is a breed that has been suffering from some loss of genetic variation due to the heavy use of only a few males. Concerns have arisen and crossbreeding has been discussed as a way to manage gene loss. Four breeds has been taken into consideration for this purpose; schipperke, finish lapphund, Norwegian buhund and Norwegian elkhound, black. These breeds has been tested theoretical by a comparison of mentality and health.

Vaktelproduktion för ägg och kött

The aim of this study is to review the commercial quail production for eggs and meat in the world. Another aim is to review the potential for increased production. Globally the quail production is very small, except in China where it is the second largest poultry industry. The production globally is small despite the quail's rapid growth, early sexual maturity and its high feed efficiency. The quail is also used as a laboratory animal and can be reared to be released in hunting areas.

Extrem hundavel : ett välfärdsproblem för dagens rashundar

For centuries Inbreeding has been used to refine traits in dogs, making desired traits more hereditary and thereby, different breeds have been invented. Breed standards have been written for each of these breeds, describing in detail the different characteristics of each breed. When humans start to choose which animal to breed from, so called artificial selection, taste is put before function and the laws of nature, the natural selection, cease to apply. During this development, pedigree dogs have gone towards more and more extreme exterior characteristics and the dogs may have inherited various, more or less, severe problems for example compromised vision, impaired ability to move and difficulties to breathe. However they can still survive and reproduce because humans provide them with the conditions to do so.

Phenotyping of Bali cattle and interviewing farmers in Indonesia - a minor field study

Among the Indigenous cattle breeds in Indonesia, the Bali cattle is the most preferred by small farmers. The Bali cattle is a beef breed, and is considered to have several advantageous characteristics and to be well adapted to the country?s harsh environmental tropical conditions with drought and rain. The main aim of this project was to phenotype of Bali cattle from different locations in order to identify and document diversity within the Bali cattle breed based on their observable characteristics, to compare cattle from different areas and production systems to see the effect of management on phenotype. In this study, 107 cows and bulls of the breed Bali cattle, from Kalimantan, Sumatra, Lombok and Bali were phenotyped.

Den licensierade vargjaktens betydelse för vargstammen

In October 2009, a new decision was made concerning the administration of predators which resulted in a new wolf policy in Sweden. This meant that the wolf population now should be limited to 210 individuals by harvest. The new policy also recognized that the public acceptance of this species must increase and the genetic status improved. In the 17th of December a decision was taken by the Swedish parliament that it should become legal to hunt wolves in Sweden. The wolf hunt resulted in debate on a large scale amongst people, some thought of it as a good decision while others thought it was wrong.

Klosjukdomar hos hund : en litteraturstudie och en fallstudie i den Svenska Riesenschnauzerpopulationen

Various problems with nail disorders have been noticed in the Swedish population of Giant Schnauzer, but the frequencies of these problems are unknown. This could be due to the fact that bad nail quality has several differential diagnoses and lack of diagnostic criteria and diagnostic codes for nail disorders. The main purpose of this study is to review different types of claw defects and diseases of the nail bed in dogs, and to classify and evaluate the proportions in the Swedish Giant Schnauzer population. The nail is a specialized part of the skin. The quick will strengthen and protect the third phalang against the surrounding.

1 Nästa sida ->